#bg {
    height: 450px;
    background: url('bg.png');
    position: relative;
    /*overflow: hidden;*/
    width: 80%;
    text-align: center;
}

.score{
    height: 50px;
    width: 50px;
    position: absolute;
    top: 20px;
    left: 20px;
    z-index: 3;
}


.BottomPipe {
    margin: 0;
    padding: 0;
    background: url('pipe.png') top;
    width: 60px;
    overflow: hidden;
    height: 120px;
    position: absolute;
    bottom: 0px;
    left: 100%;
}

.TopPipe {
    margin: 0;
    padding: 0;
    background: url('pipe.png') bottom;
    width: 60px;
    overflow: hidden;
    height: 120px;
    position: absolute;
    top: 0px;
    left: 100%;
}

.index {
    width: 950px;
    margin: 0 auto;
    padding: 0;
    text-align: center;
}

.bird {
    height: 28px;
    width: 40px;
    background: url('bird.png');
    position: absolute;
    bottom: 50%;
    left: 186px;
    z-index: 3;
    animation: birdFlap 0.2s steps(3, end) infinite alternate;
    transition: transform 0.3s;
}

